foxnews.com – To view this page ensure that Adobe Flash Player version 10.2.0 or greater is installed. Now Playing Parents of murdered veteran and aid worker talk publicly The family of an American aid worker and former Army Ranger who was beheaded in a video released by Islamic State militants said on Monday their “hearts are battered, but they will mend.” Peter Kassig, 26, who also was known as Abdul-Rahman after he converted to Islam during his captivity, had been held by the Islamic State, also known as ISIS or ISIL, since October 2013 when he was abducted while delivering food and medical supplies to wounded Syrians in eastern Syria.